The man accused of killing a New Jersey teen and hiding her body in a shallow grave tried to hang himself in jail, according to a woman claiming to be his ex-girlfriend.

Jack Fuller, 39 – charged in July with murdering Brick Township honor student Brittney Gregory, 16 – allegedly made the suicide bid after being beaten up by other inmates in the Ocean County Jail.

Claiming Fuller has had his jaw broken and ribs fractured by fellow jailbirds and now fears for his life, the woman said he was attacked after being moved from a special housing unit to the general population.

Fuller’s court-appointed lawyer, John Goins, declined to comment on the claims. Jail warden Theodore Hutler Jr. did not return calls.

The woman, who identified herself as Barbara Capuzzio, made the claims to an Asbury Park Press reporter. Subsequent efforts by The Post to locate Capuzzio were unsuccessful.

However, Hutler has previously confirmed Fuller spent time in the jail’s medical unit, as well as a special protective unit that’s used for inmates.

“He has had some incidences with other inmates,” Hutler has said.

Ocean County prosecutor spokesman Robert Gasser said the office is not aware of any assault on Fuller.

Early in Fuller’s incarceration, Gregory’s family told The Post they’d heard the accused killer’s jaw was broken in a jailhouse beating. Law-enforcement sources said he entered jail with a fractured jaw from a previous incident.